Platelets can be prepared by using a centrifuge to separate the platelet-rich plasma from donated whole blood. Platelets from several different donors are then combined to make one tranfusable unit.
Using this process, one donor can contribute about four to six times as many platelets as a unit of platelets obtained from a whole blood donation. Platelets are stored at room temperature for up to 5 days. They must receive constant gentle agitation to prevent them from clumping. Platelets are most often used during cancer treatment as well as surgical procedures such as organ transplant, in order to treat a condition called thrombocytopenia, in which there is a shortage of platelets.
They are also used to treat platelet function abnormalities. Since platelets must be used within 5 days of donation, there is a constant need for platelet donors.
Learn more about donating Platelets ». Plasma is the liquid portion of blood; our red and white blood cells and platelets are suspended in plasma as they move throughout our bodies. It helps us maintain a satisfactory blood pressure and volume, and supplies critical proteins for blood clotting and immunity. It also carries electrolytes such as sodium and potassium to our muscles and helps to maintain a proper pH acid-base balance in the body, which is critical to cell function.
Plasma is obtained by separating the liquid portion of blood from the cells. Plasma is frozen within 24 hours of being donated in order to preserve the valuable clotting factors. It is then stored for up to one year, and thawed when needed. Plasma is commonly transfused to trauma, burn and shock patients, as well as people with severe liver disease or multiple clotting factor deficiencies.
Have you ever wondered exactly what happens to the blood you donate at the American Red Cross? Your blood goes on an amazing journey! You can learn about all the steps your blood goes through before it reaches a recipient in this informative video. Types of Blood Donations. How Blood Donations Help. Get the Blood Donor App. What Happens to Donated Blood. What Happens to Donated Blood Your blood journeys through many steps and tests that ensure our blood supply is as safe as possible and helps as many people as possible.
Your Donated Blood's Journey. After donating, you sit in an observation area, where you rest and eat a light snack. After 15 minutes, you can leave. After your blood donation:. Your blood will be tested to determine your blood type and your Rh factor. The Rh factor refers to the presence or absence of a specific antigen — a substance capable of stimulating an immune response — in the blood.
You'll be classified as Rh positive or Rh negative, meaning you do or don't carry the antigen. This information is important because your blood type and Rh factor must be compatible with the blood type and Rh factor of the person receiving your blood.
Your blood will also be tested for bloodborne diseases, such as hepatitis and HIV. If these tests are negative, the blood is distributed for use in hospitals and clinics.
If any of these tests are positive, the donor center notifies you, and your blood is discarded. Explore Mayo Clinic studies of tests and procedures to help prevent, detect, treat or manage conditions.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version. Overview Blood donation is a voluntary procedure that can help save the lives of others. Whole blood donation This is the most common type of blood donation, during which you donate about a pint about half a liter of whole blood.
Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references FAQs about blood and blood donation. Accessed Feb 8, Requirements by donation type.
American Red Cross. The programme is run with mainly two spins-heavy spin e. The heavy and light spin configuration varies with manufacturer and model. Apheresis is a procedure where required single or more than one component is collected, and the rest of blood components are returned back to the donor.
The working principle of apheresis equipment is either by centrifugation different specific gravity or by filtration different size. The most commonly used equipments use the centrifugation principle and also give leucodepleted products. In this method, fixed quantity of blood is collected in a bolus called as Extracorporeal volume ECV and the required component e.
Platelets is separated and collected in the collection bag and the other components e. The Intermittent equipment uses single vein access for both collection and return. One cycle consists of-one ECV whole blood collection in kit bowl, centrifugation of bowl to separate components, collection of required component platelets in collection bag and finally return other constituents like red cells, leucocytes and plasma to donor. This cycle is repeated till therapeutic dose is attained.
In continuous working equipment, two simultaneous phlebotomies are done: One for the collection and other for the return. The collection, centrifugation, component collection and return occur continuously and simultaneously. Each type has its own advantage and limitation.
The various components that can be collected are - double unit red cell collection red cells , single donor platelet SDP harvesting platelets, leucapheresis harvesting granulocytes, peripheral blood haematopoietic stem cell , plasmapheresis collecting normal plasma and therapeutic plasma exchange for exchanging with normal plasma after collecting and discarding patient's plasma.
Apart from being fit as per the whole blood donation criteria, additional criteria to be met for apheresis donors include prominent accessible vein for withstanding apheresis procedure and weight more than 55 kg. In spite of strict guidelines for donors of apheresis procedures, advanced equipments like continuous apheresis equipment have allowed complicated procedures like therapeutic erythrocytapheresis and leucapheresis of small children for thalassemia and leukaemia respectively to be performed safely in children weighing kg without increased morbidity[ 5 ].
The donor should be asked to sign a consent form in the language which he understands after being explained the procedure and the risks involved. Certain investigations should be done and all parameters should be within the acceptable range prior to subjecting the donor for apheresis procedure such as complete blood count, total proteins including albumin, globulin, same ABO grouping.
Donors should have the haemoglobin level of Donors who have ingested aspirin or similar antiplatelet drugs in the last 72 h and clopidogrel or ticlopidine, the plateletpheresis should be deferred for 3 and 14 full medication-free days, respectively. Plateletpheresis should not be done on donors with personal and family history of bleeding tendency.
In a donor who undergoes plateletpheresis, the procedure can be repeated after 48 h. This is restricted to a maximum of two procedures per month and 24 procedures in 1 year. Granulocyte concentrate is collected mainly by apheresis and indications are rare; One such indication is to support patients with abnormal neutrophil function and persistent infection[ 6 ]. Peripheral blood stem cells PBSC are harvested using continuous or intermittent cell separator.
Donors for leucapheresis, both autologous and allogeneic PBSC harvest may receive drugs like growth factors G-CSF , hydroxyl ethyl starch, dexamethasone etc.
Some donors may have adverse reactions to such drugs. Adequate precautions to manage such situation have to be taken or donors may have to be rejected in some cases. The maximum plasma that can be collected per procedure is ml in a donor weighing more than 55 kg.
Any fit donor can undergo a maximum of two procedures per week and 24 procedures in 1 year. Apheresis procedure allows the collection of different blood components from the same donor during a single session. Donors should be observed closely during apheresis for adverse events such as citrate toxicity manifested as perioral paresthesia, tingling, twitches and headache, fainting attacks, tachycardia, dyspnoea etc.
Red blood cell loss incidental to the procedure should be no more than 25 ml per week. The various Blood components that can be prepared from component preparation or apheresis procedures are as follows:. Granulocyte concentrates now very uncommon , autologous or allogeneic peripheral blood hematopoietic stem cell collection-PBHSCT apheresis.
At present, plasma fractionation is driven by demand for two protein concentrates-albumin and immunoglobulin. Blood products can be modified to make blood transfusion safer and accessible to avoid adverse transfusion reactions in patients susceptible for them. The products can also be modified for better therapeutic outcomes by leucodepletion, volume depletion, irradiation, cryopreservation, rejuvenation, etc.
Such products are called leucocyte reduced but not leucocyte depleted. Leucocyte depletion is achieved only by filtration. The main advantages of BC removal are micro aggregate formation during storage is greatly reduced and febrile non-haemolytic transfusion reactions FNHTR are reduced without any extra effort. In terms of safety and cost-effectiveness, the most rational approach seems to be to recommend the use of buffy-coat-depleted RBC to prevent FNHTR in low-risk patients, while leucoreduction by filtration should be restricted to patients with the well-known indications.
Pre storage: Immediate filtration within 48 h from collection before or after component separation. Process is done when leucocytes have not dissociated or broken or cytokine released. On demand also called as Lab side-This is done only on demand. Bags with built in filters ensure a closed system when used with sterile connecting device SCD and are also easy to operate.
Pre transfusion also called as bedside: This is done by spiking blood component bag with a specialized transfusion set having leucocyte filter with continuous leucoreduction during transfusion.
Here the effect of cytokines cannot be avoided. All neonatal and paediatric transfusions for children less than a year. To avoid human leucocyte antigen HLA alloimmunisation in patients requiring multiple transfusions who may develop platelet refractoriness. To avoid immunomodulation in recipients and prospective recipients of solid organ kidney , haematopoietic stem cell transplant and patients with malignancies.
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